Does our body oxidize when we breathe oxygen? Can we get 100 percent O2?

Of course, the body uses O2 as oxidizing agent; Ideally, it is used to fire the breathing chain in the mitochondria. He also oxidizes everything possible in the body, which should not be oxidized; To this end, the body has developed a bunch of detoxification methods to minimize this problem.

If you were to breathe pure oxygen (at atmospheric pressure), then your breathing chain would run hyperefficiently, so the body has much more energy to provide and can afford much more — for example, you could run longer and faster. On the other hand, the cell damage would also be caused by the undesirable oxidation, and in the long term the repair measures of the body would be limited.

Many people occasionally breathe pure oxygen as part of medical therapies, e.g. in all possible accidents or emergencies, but also Christian in heart failure. The reason is that the heart is relieved because more oxygen can be transported with each heartbeat than normal. In the short term this is not a problem, long-term as described above very well; but sometimes there is no choice if the patient is in constant danger of life without the extra oxygen.

Oxygen poisoning is something completely different; To this end, oxygen must be inhaled at overpressure, and in a short time there is evidence of poisoning from noise to unconsciousness and coma. This can happen, for example, divers, and it is acutely life-threatening.